Is Caffeinated Water a Solution—or a Problem—When It Comes To Staying Hydrated?

And unfortunately, dehydration can lead to pretty rough (and surprising) side effects, such as muscle cramps, mood problems, allergy and asthma symptoms, decreased immunity, and more.

But between graduate school, work, playing volleyball, and maintaining a social life, I may not make it the whole day without caffeine (and, let’s be real, some flavor in my beverages).

Given this predicament, you can imagine my joy at the discovery of caffeinated flavored water packets at Walmart. One packet has 120 milligrams of caffeine (that’s more than coffee!).

I've also become acquainted with Celsius, a brand of functional energy drinks containing green tea, water, vitamins, ginger root, and other ingredients, that typically have 200 milligrams of caffeine. Some volleyball players I know will drink a can of it instead of bottled water in between sets.

Is caffeinated water what we’ve been looking for all along in the struggle to stay hydrated in the midst of needing extra energy? Or is it too good to be true, especially considering how dehydrating caffeine, a diuretic, can be?

The pros and cons of caffeinated water

This type of drink does have unignorable benefits. “Caffeinated water provides hydration along with the stimulating effects of caffeine,” says Sarah Lynn Quick, RDN, CDN, a registered dietitian and Cure nutrition advisor. “If you need a quick boost of energy, caffeinated waters or energy drinks will do the job.”

Further, it can even be considered the “better” option. “When consumed in moderation, caffeinated water can be a healthier alternative to more processed caffeinated drinks, such as sodas,” adds Brittany Werner, RDN, LDN, director of coaching at Working Against Gravity.

Some even have nutrients. Quick says drinks like Celsius often contain B vitamins, for example, which enhance its effects since they help convert fuel into energy.

If you’re looking for a more gradual release, Celsius may be the way to go, too. “Celsius drinks contain caffeine from the guarana plant, which can offer a slower release of caffeine compared to coffee, potentially offering a longer-lasting effect without the sudden crash,” says Michelle Routhenstein, RD, CDCES, CDN, a registered dietitian nutritionist and preventive cardiology dietitian at EntirelyNourished.com.

While these drinks can contribute to your water intake, there can be a bit of “canceling out,” so to speak, depending on the amount of caffeine, according to Routhenstein. “Be mindful of the caffeine content, as excessive consumption may counteract the hydrating effects due to the caffeine’s diuretic properties,” she says.

So, despite the pros, it’s also important to be aware of the real potential harms. “The major downside to caffeinated water is the potential to overdo it on caffeine consumption if using these flavorings in your water on a regular basis or as a main source of hydration,” Quick says.

Routhenstein warns about drinking caffeine in excess, too, saying that doing so can lead to jitteriness, disrupted sleep, and increased heart rate and blood pressure. Werner adds dehydration, nervousness, restlessness, and nausea to the list.

How much caffeine is safe?

So what amount is considered “okay” to consume? According to the FDA, up to 400 milligrams of caffeine daily is safe for healthy adults. That’s about two cans of Celsius or a little over three packets of Walmart’s caffeinated flavor water.

At the same time, keep in mind that all bodies are different. “Individual tolerance to caffeine varies, and those with medical conditions should check with their doctor on how much is safe to consume,” Quick says.

Additionally, amount isn’t the only consideration—timing is, too. “It is better to space out caffeine intake to avoid potential negative side effects and allow your body to process it gradually,” Routhenstein notes.

The overall takeaways and better options

Ultimately, this question of whether the caffeinated water is a solution or problem comes down to that vague word: moderation.

More specifically, Quick suggests one serving or less per day, also depending on any other sources of caffeine you consume. She also encourages opting for caffeinated water over Celsius drinks or energy drinks due to the hydration benefits, slightly lower caffeine content, and fewer negative ingredients.

At the same time, don’t forget that caffeinated water and water are not the same, unfortunately. “[Caffeinated waters] are not meant to be an alternative to water,” Werner says.

Routhenstein doesn’t advise caffeinated water, either, or at least encourages people to find ones that aren’t so high in the stimulant. “To prioritize overall health and heart well-being, opting for alternatives with lower caffeine content or plain water may be a better choice,” she says. “An even better option [is] Cure’s energizing tea mixes, which are made with natural ingredients like green matcha and black tea, no additives or sugars, lower caffeine content at 55 milligrams per serving, and contain electrolytes to optimize hydration and boost mental clarity.”

My takeaway? Think of caffeinated water more as a sub for your second (or third) coffee or soda rather than your regular H2O.